Ion deposition printing is well known, and one of many U.S. Pat. Nos. describing ion printing apparatus is U.S. Pat. No. 4,494,129, granted Jan. 15, 1985 to Delphax Systems. Ion deposition printers may be purchased from various sources, including from C. Itoh Electronics Company, 2515 McCabe Way, P. 0. Box 19628, Irvine, Calif. 92713-9628.
Ion deposition printers provide an excellent printing capability, but have certain shortcomings. In this regard, it is noted that ion deposition printers apply relatively high levels of pressure between the output roller and the electrostatically chargeable drum as the toner is being applied to the sheet being printed. In the case of sheets of pressure sensitive labels which are fully coated with adhesive, and are mounted on backing sheets, ion deposition printing has the effect of curling up the edges and corners of the sheets, so that the sheets cannot practically be stacked, or used.
Accordingly, a principal object of the present invention is to provide a method for printing sheets of labels or similar materials mounted on backing sheets, by the ion deposition method; and a related object is to provide an improved dual thickness label-adhesive-backing sheet combination which may be used in ion deposition printers, without the curling problem discussed above.